| Gears are important mechanical parts in the national industrial system.They are widely used in the fields of automobiles,ships,aerospace,weapons,etc.,and the annual demand continues to rise.With the continuous development of science and technology in innovation,the requirements of modern equipment for gear accuracy are also increasing.The gear chamber of Dalian University of Technology grinds the highest level(class 1)master gear in the international standard ISO 1328-1: 2013(the same below)using the gear grinder,and the roughness Ra of the tooth surface along the involute direction is about 0.2 μm,which is larger than the accuracy of the tooth profile of the gear.Larger tooth surface roughness will increase the measurement uncertainty of tooth profile deviation and affect the performance of master gears.In order to solve the problem of large tooth surface roughness by grinding class 1 master gears,this paper proposes a new tooth surface generation grinding and polishing method and develops a new high-precision gear tooth surface generation grinding and polishing device.First of all,in the process of gear polishing,there is a phenomenon that the linear velocity at the graduation circle is zero,which results in "medium convex" or "medium concave" teeth.The process of changing the center distance help to change the linear velocity at the node periodically,which can improve the phenomenon of "convex" or "concave" teeth;Then according to the influence of the installation error of key components on the polishing accuracy of the gear,it is concluded that the installation tilt of the gear in the error-sensitive direction has the greatest impact on the machining accuracy of the gear.Using the high-precision dense ball bushing can reduce the rotation error of the mandrel to below 0.2 μm,besides,refining and trimming important axis sections and positioning surfaces of key components.Moreover,the end surface of the rotary shaft after being plastic-coated is scraped,which improves the axial positioning accuracy of the high-precision gear tooth surface generation grinding and polishing device and reduces the dynamic and static friction coefficient between the gear and the end surface of the rotary shaft;Finally,according to the principle of phase matching,the tooth surface grinding and polishing device is precisely assembled,and the parallelism of the upper end surface of the sleeve relative to the upper end surface of the cast iron round table is reduced to less than 0.6 μm.Therefore,the assembly accuracy of the high-precision gear tooth surface generation grinding and polishing device is further improved.Using the developed highprecision gear tooth surface generation grinding and polishing device to carry out the research and polishing experiment on the class 1 master gear.The experimental results show that the orientation of the tooth surface texture changes after the grinding and polishing of the device,and the roughness Ra of the tooth surface along the involute direction decreases from about 0.2 μm to less than 0.046 μm,and the roughness Ra of the tooth surface along the tooth width direction drops to about 0.039 μm.By grinding and polishing,the surface roughness of the class 1 master gear tooth surface in two directions is significantly reduced,and the performance of the class 1 master gear is improved.In this paper,a device for developing and polishing a high-precision gear tooth surface using a variable center distance process is developed,which avoids the situation that the linear velocity near the gear node is zero during the polishing process,and achieves a significant reduction in the roughness of the tooth surface and changes the texture orientation of the tooth surface without reducing the accuracy of the high-precision gear.The roughness Ra of the tooth surface of class 1 master gear can be reduced to the nanometer level,and the device improves the performance of class 1 master gear and has important scientific significance for the precision machining technology of class 1 master gear. |
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